We propose studies on the fate of natural C19-steroids in explants of immature and mature canine prostate and epididymis and human prostatic adenoma and adenocarcinoma, morphologically maintained in serum-free medium, with the overall objective of attributing effects on epithelial structure and biochemical functions to individual intracellular androgens. Effects of inhibitors of steroid metabolism and specific 5 alpha-dihydrotestosterone binding on the disposition of the selected substrate in organ culture will be investigated. Evaluation of the response of explants with immature or retrogressed epithelium to the androgen supplement will be by morphometric assessment of gross and fine structure, assay of dihydrotestosterone receptor and determination of the activities and isozyme patterns of prostatic acid phosphatase and L-ornithine decarboxylase and epididymal alpha-mannosidase. BIBLIOGRAPHIC REFERENCES: Morfin, R.F., Leav, I., Charles, J-F., Cavazos, L.F., Ofner, P. and Floch, H.H. Correlative Study of the Morphology and C19-Steroid Metabolism of Benign and Cancerous Human Prostatic Tissue. Cancer 39: 169-186, 1977 (to appear in April issue). Ofner, P., Vena, R.L., Barowsky, N.J., Singer, R.M. and Tashian, Jr., A.H. Comparative C19-Radiosteroid Metabolism by MA 160 and HeLa Cell Lines (accepted by In Vitro on February 28, 1977).